The goals of this study are the following: (1) To determine the maximum tolerated dose of CPT-11 when administered every 3 weeks to patients with recurrent malignant glioma. (2) To determine toxicities of every three-week dosing. (3) To characterize pharmacokinetics of CPT-11 and its metabolites, SN-38, SN-38 gluconide (SN-38G) and APC. (4) To assess antitumor activity. We wish to use the expertise of the GCRC in drug administration, patient care, and patient teaching to achieve the study goals.